While developing an example for the heartbeat component, i run into problems dealing with file handling in php. The problem comes from race conditions by reading and writing (updating) the same files. I must admit, it still needs some time to solve this problem in a sufficient way, but i'm on it.
Nevertheless, two shiny links where found by my preferred search engine and it would be a shame to not share them.
The first link has the title handling json like a boss in php. The page shows you how to encode and decode json files in php. What i liked very much, it also contains an error handling part. Shame on my side, i was not aware of the jsonlasterror function, now i am .
The second link headlines itself PHP File-handling tips and tricks and it contains a lot. I like, that the author puts back the SPLFileObject and SPLFileInfo into the limelight.
Even better, i wasn't aware of the available stream "php://temp". Thank you both!